Tube-end beveling and sealing device



' 1 642 456 Sept. 13, 1927. I c. E. I BP V TUBE min BEVELING AND SEALI'NG mwlcfi Filed Nov. 50, 19 26 i latentedsept. 13,1927;

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4 OF MASSACHUSETTS.

roan-men n'nvnnrlve ann'snatme same.

ap lication filed November so, me. Serial No. 151,040.

This invention relatesto the manufacture of rubber tubes particularly such as are designed for use as inner tubes for pneumatic tire casings. It has particular referenceto 5. the production of beveled ends on such tubes before they are bent into. endless form and .spliced, and to a device for simultaneously beveling the ends of such a tube and sealing them to the mandrel-upon which it is Va canized. It is the object of the invention to produce a straight bevel on the end of the tube in contrast with the blunt or rounded bevel produced by certain prior art devices. I Referring .to the drawings: Fig. 1 is a view of a tube mounted upon a vulcanizing mandrel showinga tube end beveling and sealing device-in place;

Fig. 2 is aside View partly in section showing a beveling and sealing device as -formerly constructed;

.Fig. 3 is a detail of the end of a tube after having been vulcanized by-the use of the.

: device shown in Fig. 2;

Fig. '4 is a sectional view corresponding to the upper portion of Fig; 2, but showing my improved beveling and-sealing device;.

Fig. 5 is a detail showing my improved device in-place upon a tube; and a Fig. 6 is a view similar to Fig. 3, but 1 showing the result of using the device illustrated in F ig. 42 U It has been customary in the manufacture .of inner tubes to mount them upon a cylindrical mandrel, either straight or bent into circular or spiral form, and to bind the ends of the'tube to the mandrel by some sort of device which siinultaneously'seals the ends of the tube :against ingress of steam and d din rm a mM mK- bevels or'tapers theends of the tube. This bevel or taper of the tube ends is desirablethe tube is later spliced into endless.

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cnszams nnean minim, or Nonrmrron, inssacnusnr'rsassmuon To m max nurnaacourm. or onxcornn FALLS, 'uassscnusnms, a coaronarrou of work. In spite of this the taping method of beveling the tube end has been used for many years particularly upon straightm ans drels. Where the tubes are vulcanized upon circular mandrels the use of tape is not quite 'so easy as the tape must be puton by hand .or by more complicated machinery-than is needed where the tubes are cured. upon. straight mandrels.

shown in Fig 2, or a metal clamp suc as is shown-in atents 1,391,784 granted September 27, 1921 or 1,450,320, granted April 3, 1923, has been used.- This ring 13 had a cylindrical bore 14 and a body portion 15 of generally uniform thickness, but with an outside taper 16 at one end. The skived ring was mounted upon the mandrel and.

tube as shown in Fig. 1 with the tapered portion lfidirected toward the tube and the body portion 15 resting in' part upon the mandrel. The ring 13 was constructed of vulcanized rubber and of a diameter less." than the diameter of the mandrel- 10 so that duringthe cure it exerted a steady compres-" 'Fi'g. 3. It will be observed that the tube has a blunt end '17. The use of a rin this character always produces. the b unt end 17, and may produce either a recess 18 or the form shown in dotted lines in Fig. 3,

depending upon the length of the tapered As an alternative to this method of manufacture, the skived rin 13,

'portion 16. Perhaps the reason for this action can be described better after my improved type of clamp-has been submitted. f i

A clamp constructed in accordance with my invention is shown in Fig. .4. It will be seen that this comprises a molded ring- 19 having a cylindrical 'bore 20. The outer surface of the ring isformed with a gradual taper 21 leadin u to a point of maximum thickness 22, 'w ic in ,turntapers ofi suddenly at 23 and'merges into a gradual taper 24. When such a-rin is stretched the region 22 of greatestthic hardest to stretch and therefore will exert the-maximum contractive force. This. is iless will be the Y lustrate'din 'Fi 5 which shows the device j mounted upon t e end ofa tube. The tube endisshowni'n' an line in this be; I

fore the clamp has be to mold the soft rubber of the tube an in dotted line after this'molding has been completed. The easiest point of the tube end to mold is the very end since, as is clearly shown in this figure, this portion of the ru ber is an ported only at one side. It can be pressed own toward the mandrel and have a slight flow toward the right in Fig. 5 unrestrained except by the natural reluctance of the rubber tofl' The resistance to molding ofiered by t e rubber of the tube end increases as the end of the tube is left until the maximum resistance is offered at a point about under the numeral 22 in this figure. By my improved device the pressure is pro ortioned as required by the resistance 0 ered by the tube and the difficulties experienced byv the use of the ring shown in Fig. 2 are avoided.

This latter form of ring exerts a uniform pressure (except at the short tapered end) on account of the uniform thickness: of the body of the rubberband. The uniform pressure, however, produces a non-uniform elfect due to the lack of uniformity in the resistance to flow ofieredby In consequence, the point at the end of the tube where the flow is easiest will be beveled abruptly as in Fig. 3. The device of Fig. 4, however, exerts a non-uniform ressure which coacts with the non-uni orm resistance to flow of the tube end to produce a uniformly tapered bevel 25 as shown pressure a maximum at a circumference located m1dthe tube and.

.vice constructed of a ri 3. The process of making a rubber tube having a straight beveled end which comprises ap lying to the. end of the tube 9. comes in each direction from way of the bevel tobe produced.

The process of making a rubber tube havinga straight beveled end which comprises ap lying to the end of the tube a pressure ecreasing in each direction from a maximum at a circumference located midway of the bevel to be produced, and vul-.

canizing the 'tube while maintaining said pressure.

5.- A tube end beveling and sealing device constructed of a ring of resilient material having a thickness intermediate its,

mediate section of greater thickness than the thickness ad'acent either end.

7. A tube en beveling and sealing de ,of resilient material having an interm iate portion possessin greater contractive force when the ring is stretched than the portions of the ring adjacent either 'end.

CHARLES EDGAR MAYNARD. 

